Hibernate problem: One-To-Many association

[Eduards Sizovs]

Hi there!

I have a problem with Hibernate:
- Two classes - Company and CompanyContact have One-To-Many relation. When persisting a Company with some Contacts set, Hibernate generates
INSERT statement which does not have FOREIGN KEY set in Contacts. Unfortunately, I cannot spot why and hope for Your assistance,

Mapping for CompanyContact

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
	"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="lv.konkurent.domain">
	<class name="CompanyContact" table="COMPANY_CONTACTS">

		<id name="id" column="id" type="long">
			<generator class="increment" />
		</id>

		<property name="address" column="ADDRESS" type="string"
			length="80" />
		<property name="fax" column="FAX" type="string" length="20" />
		<property name="phone" column="PHONE_NUMBER" type="string"
			length="10" />


	</class>
</hibernate-mapping>

Mapping for Company

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
	"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="lv.konkurent.domain">
	<class name="Company" table="COMPANIES">

		<id name="id" column="id" type="long">
			<generator class="increment" />
		</id>

		<property name="login" column="LOGIN" type="string" length="60" />
		<property name="password" column="PASSWORD" type="string"
			length="60" />
		<property name="companyName" column="NAME" type="string"
			length="80" not-null="true" />
		<property name="registrationCode" column="REGISTRATION_CODE"
			type="string" length="11" />

		<property name="anonymous" column="ANONYMOUS" type="boolean"
			not-null="true" generated="always" />

		<bag name="contacts" cascade="all">
			<key column="COMPANY_ID" />
			<one-to-many class="CompanyContact" />
		</bag>

	</class>
</hibernate-mapping>

SQL

Hibernate: select max(id) from COMPANIES
Hibernate: select max(id) from COMPANY_CONTACTS
Hibernate: insert into COMPANIES (LOGIN, PASSWORD, NAME, REGISTRATION_CODE, EMAIL, DESCRIPTION, SERVICES, WEB_ADDRESS, id) values (?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: select company_.ANONYMOUS as ANONYMOUS3_ from COMPANIES company_ where company_.id=?
Hibernate: insert into COMPANY_CONTACTS (ADDRESS, FAX, PHONE_NUMBER, id) values (?, ?, ?, ?)
Hibernate: insert into COMPANY_CONTACTS (ADDRESS, FAX, PHONE_NUMBER, id) values (?, ?, ?, ?)

Thank you,

[Rahul Babbar]

Your companycontact hbm should have a relationship to Company hbm,
like

 
<property 
        	name="company" 
            column="COMPANY_ID" />

and your CompanyContact Pojo should have a
private Company company;
and getters and setters for it.

[Eduards Sizovs]

Thanks for response,

In this case, it requires manual setting of CompanyID property, otherwise it inserts null.

Is it possible for Hibernate to determine Foreign Key for associated entities from their parent?

[Rahul Babbar]

It will set companyId as null in the CompanyContact table if any of the following holds true.
1. One do not have an assocation, but only have a column in the CompanyContact and never sets that property.
2. If one has an association, but is not doing something like "companyContact.setCompany(contact);"
3. If one has both an association as well as setting the company in companyContact as above, but one is not setting the companyId in company and the id generation in Company hbm is defined as "assigned".

[Rahul Babbar]

Eduards Sizovs wrote:
Is it possible for Hibernate to determine Foreign Key for associated entities from their parent?

I dont think so,
since the foreign key exists in the child table and not in the parent table, you need to have the association in the child hbm atleast(which was missing from your original set of hbms)